Classic Gameboy Cellphone Cartridge – Thought page

So a comment on Reddit got me thinking: How hard would it be to make a specialty cartridge for the Classic Gameboy handheld that contains a GSM radio, an antenna, and possibly a battery? Calling would be a secondary function, but the ability to text via Classic Gameboy. That’s a neat idea.

Step 1: Research. How many different ways are there to make cartridges?

Turns out there’s quite a few. One is just a PCB with a flash chip and possibly a memory controller. The other, more feasable method will be the STM32F4 method. Why not stand on the shoulders of giants?

Step 2: How would it work?

With any cartridge, you need a ROM, and since we’re using a GSM module, we’ll need a way to communicate. Option 1: PCB with flash chip and memory controller, you’d have to talk over the link cable socket. The basic method doesn’t support games that have saves or writing back to the chip.

Option 2 is the way we could easily implement this. Dhole seems to have figured out how to make the Gameboy read & write back to an emulated cartridge. This is to our advantage.

I have literally no idea how difficult this would be, but here is the basic concept:

Part 1: Software.

The ROM for the gameboy would require a basic UI to control the modem. Commands like calling, texting, and sending data (if supported by the GSM module) would be written back to the cartridge’s writable memory area (think save file, with the command being the part that is saved). The STM32F4 would then read the memory area every X number of cycles and execute commands to the GSM module. You’d need two sets of programming. One to run the GUI and save commands, and another piggyback program on the cartridge emulator to read the saved data periodically and do whatever it wants.

Part 2: Hardware.

For the hardware, we’d need either an STM32F4 or other compatible piece of hardware. Since the software to emulate a cartridge is already written and the process well documented, why reinvent the wheel. We also need a GSM module. For just texting, a $10 SIM800L Arduino module would work well. If you want to add voice, you’ll need to upgrade to something like the Adafruit Fona module (About $40 right now) or some other GSM Voice module (I’ve found them between $20 and $90 on eBay)

If you want to go completely crazy, you could use something like an Odroid or Raspberry Pi Zero and reinvent the wheel, using the research done and the example code provided.

That’s all I have now. I have no idea how to make this a reality, but it seemed like it would most certainly be possible to accomplish.